Glucosephosphate isomerase (GPI) of the teleostFundulus heteroclitus (linnaeus): Isozymes, allozymes and their physiological roles |
| |
Authors: | Stephen R Palumbi Bruce D Sidell Rebecca Van Beneden Glenn D Smith and Dennis A Powers |
| |
Institution: | (1) Department of Biology, The Johns Hopkins University, 21218 Baltimore, Maryland, USA;(2) Department of Zoology and Migratory Fish Research Institute, University of Maine, 04469 Orono, Maine, USA;(3) Present address: Department of Zoology, University of Washington, 98195 Seattle, Washington, USA |
| |
Abstract: | Summary In order to evaluate the role of glucose-phosphate isomerase (GPI) inFundulus heteroclitus, the isozymes and allozymes were purified and some of their physical and kinetic properties determined.Isozymes were purified from both liver (GPI-B) and muscle (GPI-A) tissue (Tables 1, 2). Gel filtration of the native enzyme and SDS-polyacrylamide gel electrophoresis indicated that all forms are dimers of approximately 110,000 Daltons (Figs. 4, 5). Although thermal stability studies revealed no differences between the allozymes, the isozymes were clearly different (Figs. 6, 7). Kinetic analysis showed further differences between isozymes inK
m for substrate andK
I for 6-phosphogluconate (Figs. 8, 9; Table 3). No significant differences were found between the allozymes of the B-locus under the conditions employed in this study.Based on the tissue specificities and the functional differences between isozymes, we propose a possible regulatory role for GPI-B inF. heteroclitus. The sensitivity of this isozyme to 6-phosphogluconate inhibition may allow GPI-B to act as a regulatory enzyme in the partitioning of carbon flow between glycolysis and the hexose monophosphate shunt.Abbreviations me
-mercaptoethanol
-
F6P
fructose-6-phosphate
-
G1P
glucose-1-phosphate
-
G6P
glucose-6-phosphate
-
G6Pase
glucose-6-phosphatase
-
G6PDH
glucose-6-phosphate dehydrogenase
-
GPI
glucosephosphate isomerase
-
HK
hexokinase
-
HMP
hexose monophosphate shunt
-
6PG
6-phosphogluconate
-
PGM
phosphoglucomutase
Supported in part by: NSF grants DEB-76-19877 to D.A.P. and PCM 77-16838 to B.D.S., NIH Biomedical grant 5-50-7RR07-041 and a grant from the National Geographic Society. G.D.S. and R.V.B. are NIH trainees supported by a training grant (No. HD00139) to the Department of Biology, The Johns Hopkins University. This is contribution No. 1052 from the Department of Biology |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|